1. Field of the Invention
The present invention relates to a wire-wound inductor, and more specifically to a wire-wound inductor having a magnetic core and small enough to be surface-mounted onto a circuit board.
2. Description of the Related Art
Wire-wound inductors have been known as coils for power supply step-up/step-down circuits used in mobile electronic devices, choke coils used in high-frequency circuits, etc. Among the known wire-wound inductors is the one described in Patent Literature 1, for example, which is structured in such a way that a coil conductive wire is wound around a ferrite core and both ends of the coil conductive wire are soldered to a pair of terminal electrodes provided on the surface of the ferrite core. Here, the ferrite core has a so-called drum shape characterized by a core and a pair of flange parts provided at the upper end and lower end of the core. Wire-wound inductors having this constitution generally allow for reduction of outer dimensions (especially height dimension), which makes them suitable for high-density mounting and low-height mounting on circuit boards.
On the other hand, another known structure of wire-wound inductors is the metal composite structure, for example, where a coil is powder-compacted using iron or iron-containing alloy and resin in a manner burying the coil in the metal. In general, inductors of the metal composite structure exhibit excellent inductor characteristics (especially energy characteristics) and are therefore suitable for power inductors in power-supply circuits and the like, for example.